1. Field of the Invention:
The present invention relates to a glare-free single focal or multifocal intraocular lens and method for using the same. More specifically the present invention relates to an intraocular lens having one or more focusing areas and a light-absorbing material for absorbing undesired light rays to minimize glare experienced by the eye of the patient in which the intraocular lens is implanted.
2. Description of the Related Art
An intraocular lens (IOL) is a transparent lens made of a synthetic or other suitable material for implantation into an eye in place of or in addition to the natural lens of the eye to correct the vision of the eye. Many different types of IOLs exist for correcting various types of vision disorders. For example, an IOL can be formed in the same shape of a natural lens of an eye that has been damaged, and can be inserted into that eye in place of the natural lens.
Alternatively, in an eye suffering from myopia, hyperopia or astigmatism, an IOL can be formed to have a bi-convex, bi-concave, plano-concave, plano-convex, concave-convex, or any other shape suitable which provides the IOL with the appropriate focusing power to correct for the error in focusing power of the eye that is causing the vision disorder. The suitably shaped IOL can be implanted into the eye in place of or in addition to the natural lens to thus correct the focusing power of the eye and eliminate the vision disorder.
Although existing IOLs are somewhat suitable for correcting visions disorders, they typically cause the eye to experience an undesirable side effect commonly referred to as a "halo effect", which is a ring of light that the person will see in the eye having the implanted IOL. A halo effect is caused due to light entering or being refracted by the IOL at certain angles which creates a glare that is sensed by the retina of the eye and thus experienced by the person. Also, reflection of light off of haptics used for mounting the IOL in the eye can also increase the intensity of the halo effect.
Although the severity of the halo effect can vary depending on the shape of the IOL and the amount of direct and ambient light being received by the eye, the halo effect can cause the patient much annoyance. Also, in certain instances, the halo effect can also adversely affect the patient's ability to read, drive a car and perform other routine activities requiring acute vision. The halo effect is discussed in more detail in an article entitled "Surgeon has insider's view of the Array multifocal IOL," Ocular Surgery News, pp. 6-12, Jan. 1, 1999.
To reduce the halo effect in IOLs having multiple focusing powers, these types of IOLs can include a darkened material at the interface between the different refractive power sections of the IOL. Examples of these types of IOLs are disclosed in U.S. Pat. Nos. 5,326,348, 5,236,452, 5,074,877, 5,019,099, 4,917,681 and 4,769,033, all to Nordan, as well as in U.S. Pat. No. 5,120,120 to Cohen.
Although these types of IOLs are somewhat suitable in reducing glare that occurs at the interfaces between lens sections having different refractive powers, these types of IOLs are unsuitable for reducing the halo effect or glare caused by light entering or exiting the perimeter of the IOL. These types of IOLs also fail to reduce reflection of light by the haptics used for mounting in the eye.
In addition, existing IOL's can block the flow of aqueous fluid, which generally flows from the back of the iris through iridectomies or holes in the iris through the pupil and into the anterior chamber. This blockage can cause glaucoma due to an increase in intraocular pressure.
Accordingly, a need exist for an IOL which reduces glare and the halo effect due to light entering or exiting its perimeter as well as light reflected off of its haptics, and which reduces intraocular pressure caused by a build up of fluid behind the iris.